Automotive air conditioning systems have charging ports that allow access to the refrigerant in the system. The charging ports are used to pass refrigerant into and out of the air conditioning systems. The charging ports are also used to attach pressure gauges to the systems.
A coupling is a device that fits onto a charging port. The coupling is connected to one end of a hose. The other of the hose is connected to a tank of refrigerant, a pressure gauge, or a manifold.
The coupling contains a valve that can be opened and closed. The coupling valve is opened in order to allow refrigerant to pass therethrough and into the air conditioning system by way of the charging port.
The air conditioning system coupling port has a interior valve. A typical type of valve found in a charging port is a Schroeder valve. The coupling port also has an exterior circumferential groove. This groove permits the use of a quick connect/disconnect mechanism.
When the coupling is installed onto the charging port, it is desirable to minimize refrigerant leakage due to cost and environmental concerns. Refrigerant leakage is minimize by installing the coupling onto the charging port with both the coupling valve in a closed position and the charging port valve in a closed position.
Some prior art valves open the charging port valve at the same time that the coupling is installed onto the charging port. For example, U.S. Pat. No. 5,293,902 shows valves in the coupling and in the charging port that automatically open as the coupling is installed onto the charging port. Because the charging port valve opens before the seals around the port are established, refrigerant leaks out. In addition, by opening the charging port valve during the installation of the coupling onto the port, the installation is made harder. This is because the operator who is pushing the coupling onto the charging port must overcome the pressure of the leaking refrigerant.
U.S. Pat. Nos. 2,473,223 and Re 34,781 show a coupling that can be installed onto a charging port with the coupling valve closed. Once the coupling is installed onto the port, a handle is rotated to open the coupling valve. The handle must be rotated numerous times in order to open and close the coupling valve. Consequently, when the coupling is removed from the charging port, the coupling valve may not be entirely closed, resulting in leakage through the valve. Furthermore, the coupling is relatively long compared to other couplings. The engine compartments of some automobiles are crowded, and lack the physical space to utilize a long coupling.
In addition, prior art couplings, such as shown in U.S. Pat. No. 3,731,705 require many parts and are therefore complicated and expensive.